Some computer systems for training and testing operators of X-ray inspection facilities for baggage screening are configured to display to an operator, on a baggage screening monitor, computer-generated contraband items or hazardous objects in an X-ray image of an actual piece of luggage. The hazardous objects have been previously recorded, and in each case are embedded in the image of the actual piece of luggage during operation.
The display of a test X-ray image in which a hazardous object is contained is referred to as image projection of hazardous items (threat image projection (TIP)). Originally, TIP concerned only hazardous objects, i.e., prohibited substances or hazardous items; in principle, however, TIP may also be extended to contraband items and other objects. When an X-ray image of a fictitious contraband item or a fictitious hazardous object is superimposed on the X-ray image of an actual piece of luggage in such a way that the fictitious object appears to be present in the actual piece of luggage, such a test image is correspondingly referred to as a fictitious threat image (FTI). Alternatively, an X-ray image of an actual piece of luggage in which an actual hazardous object has been introduced beforehand may be displayed; a test image generated in this way is referred to as a combined threat image (CTI). For further information concerning TIP, reference is made, for example, to Cutler, V. and Paddock, S., 2009, “Use of threat image projection (TIP) to enhance security performance,” 43rd International Carnahan Conference on Security Technology, Oct. 5-8, 2009, pages 46-51, DOI: 10.1109/CCST.2009.5335565.
For example, (EU) Directive Nos. 300/2008 and 185/2010 prescribe at least six hours of instruction and/or computer-assisted training every six months for operators of X-ray inspection facilities in aviation security. In addition, initial performance testing and recurring performance testing for such operators at least every three years is obligatory. (EU) Commission Directive No. 185/2010 of Mar. 4, 2010, which establishes detailed measures for implementing the common basic standards in aviation security, specifies mandatory requirements for, among other things, image projection of hazardous items (threat image projection (TIP)). By use of the above described computer system, on the one hand the knowledge and abilities of operators when target items are detected in X-ray images may be evaluated, and on the other hand operators may thus receive training, continuing training, and testing.
FTI test X-ray images may be a drawback in real-time use at security screening points. When a target item is projected into an actual piece of luggage, this piece of luggage must be checked, either beforehand or afterwards, without TIP in order to prevent a target item, possibly actually present in the piece of luggage, from being overlooked. This results in delays during operations. CTI test X-ray images are X-ray images which are not part of any piece of luggage to be checked at that moment during operations. Thus, although no additional checking of the associated inspection object is necessary, a large number of CTI test images must be kept in the system, which in addition must be routinely replaced or updated so that the operators do not consciously or unconsciously remember the test images. This results in ongoing administrative effort and corresponding costs.
There are also simulation systems for simulating an X-ray inspection facility. The system essentially comprises a computer and a database with component images which contain nonhazardous background images and hazardous foreground images. The system may combine various foreground and background images into a composite image to simulate the concealment of hazardous items and the like in a piece of passenger luggage. A composite image simulated in this way may be represented on a display for an operator being trained, who then uses a selection means to attempt to identify a foreground image, which may be a hazardous item, contained in the associated component image. The system may implement standard X-ray scanner functions, such as simultaneously displaying multiple images on the display, and stopping and starting a conveyor belt on which the passenger luggage is conveyed in order to allow accurate inspection of a certain piece of luggage, and so forth.